North American Network Operators Group
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Re: Streaming dead again.

  • From: Joe Abley
  • Date: Wed Feb 12 09:37:29 2003


On Wednesday, Feb 12, 2003, at 08:44 Canada/Eastern, Andrew Odlyzko wrote:

VOIP is likely to cause a financial upheaval in the telecom industry,
because the overwhelming fraction of revenues still comes from voice
services.  However, VOIP is likely to have only a minor impact on
Internet backbones.  The reason is that there simply isn't that much
voice traffic.
About five years ago, before Southern Cross came live and we were struggling to find trans-Pacific bandwidth to New Zealand, we looked at the idea of running our internal voice and IP traffic between NZ and the US on some kind of converged network, to take advantage of the fact that the IP peak load and the voice peak load were about eight hours out of phase.

There were lots of nice graphs that showed a big trough in voice network utilisation almost exactly corresponding with peak IP demand, and everything looked very promising until you noticed that the Y axis on the voice graph was measured in k, and that of the IP graph was measured in megs. The benefit to be gained by being able to burst into the voice trunks was so marginal that it wasn't worth spending the time thinking about how we would do it.

(Every discussion involving mixing voice and data at that company always wound up involving ATM, too, which was another good reason to back away and quietly kill the idea before any madness ensued. I hear it didn't work, though; the company in question was happily running ATM over trans-pacific STM-1s after I left, with AAL5 frames intermingled with circuit emulation. Presumably the 30% cell tax and frame-padding overhead is some kind of ritual offering to the God of "QoS", that magic deity whose name was always invoked to explain why ATM was being used for anything).

If that experience is representative of today's network as a whole, voice is not going to add much traffic to the Internet, relative to traffic that is already carried.

Of course this has nothing to do with whether the Internet today is suitable as a transport for isochronous voice services. But it's always fun to recount an anecdote in which you laugh at ATM.


Joe